[CIG-SHORT] How does Pylith number vertices on fault

[Hongfeng Yang]

Brad,

> You can't unless you modify the source code.
Can I request next Pylith release to output the coordinates of that 
vertex for tracking purpose?
Although I can add it by myself now, I (and other users) do not want to 
recompile the code after every new release.
>> When I track the slip and stress on different points on the fault, I
>> found the normal slip was indeed very large and the normal stress was
>> decreased drastically to 0, as shown in the attached figure,
>> tettrack.png. I've tried different stress drop and friction parameters
>> which all lead to very large normal slip and small normal traction using
>> a tetrahedron mesh.
>>
>> However, when I changed the mesh scheme from tetrahedron to hexahedra
>> for the same fault geometry, I can see a rupture initiated and
>> propagated on the fault. Tracking stress and slip history at one point
>> on the fault would show reasonable stress change and slip.
>>
>> Varying the tolerance would make pylith run a longer simulation, but the
>> results are not going to change based on my previous experience.
> What time stepping scheme and solver settings are you using?
>
I used a constant time step dt=0.005 s for dynamic rupture problem.
I have the following in pylithapp.cfg.

[pylithapp.petsc]
# Preconditioner settings.
pc_type = asm
sub_pc_factor_shift_type = nonzero

# Convergence parameters.
ksp_rtol = 1.0e-8
ksp_atol = 1.0e-12
ksp_max_it = 500
ksp_gmres_restart = 100

# Linear solver monitoring options.
ksp_monitor = true
ksp_view = true
ksp_converged_reason = true

# Nonlinear solver monitoring options.
snes_rtol = 1.0e-8
snes_atol = 1.0e-12
snes_max_it = 500
snes_monitor = true
snes_view = true
snes_converged_reason = true

#log_summary = true

Best,

Hongfeng